1. Field of the Invention
The present invention relates to a system for managing fluid inflow and/or outflow to an operative site (e.g., a knee joint), while also detecting whether a surgical device (such as a shaver) connected to the system is in an operational state.
2. Description of the Related Art
During arthroscopic surgery, it is necessary to have a clear field of vision, which requires reduction of blood flow into the operative site, quick removal of debris, and distension of joint spaces sufficient to maneuver surgical instruments. Fluids introduced under pressure into the operative site achieve these objectives. One such prior art fluid management system is the arthroscopy infusion pump described in U.S. Pat. No. 5,520,638, assigned to Arthrex, Inc., the disclosure of which is incorporated by reference in its entirety.
Prior art fluid management systems typically utilize one tube to deliver fluid under pressure to the operative site, a second tube to remove the fluid from the operative site while the surgical device is not being operated, and a third tube to remove the fluid from the operative site while the surgical device is being operated. That is, the fluid enters the operative site through the first tube and exits the operative site through one of the second or third tubes. Both the second and third tubes are simultaneously connected to the operative site. When the surgical device is not being operated (e.g., when a shaver trigger on a shaver is not depressed), the fluid exits the operative site through the second tube, referred to as a “cannula tube.” When the surgical device is being operated (e.g., when the shaver trigger is depressed), then the fluid exits the operative site through the third tube, referred to as a “device tube” (or, when the surgical device is a shaver, a “shaver tube”).
In some conventional fluid management systems that are configured for use with a particular surgical device, switching of the outflow path is designed to occur automatically with operation of the surgical device. When a particular surgical device is designed for use with a particular fluid management system, the controls of the two may simply be integrated to provide this feature. Surgical devices from many different manufacturers and with many different part numbers, however, may be used in conjunction with such fluid management systems. In fact, it is common for a surgeon to have a preferred surgical device—such as a preferred shaver console and/or hand piece—that may or may not be the same manufacturer as that of the fluid management system. It is also common for a surgical device from one manufacturer to be used with a fluid management system from another manufacturer. In such situations, compatibility problems can arise. For example, the fluid management system of one manufacturer is not able to detect when an attached surgical device from another manufacturer is being operated. Thus, the fluid management system may not be capable of automatically switching between the cannula tube and the device tube for outflow from the operative site, without the use of a customized detection device.
For example, one such prior art fluid management system that includes a detection device is the FMS Duo manufactured by DePuy Mitek, and as described in U.S. Pat. Nos. 4,902,277, 5,000,733 and 5,131,823, the contents of which are incorporated herein by reference. The FMS Duo utilizes a shaver detection device that is specific to each shaver hand piece cord. The shaver detection device has a male/female connector that must be custom made for each shaver hand piece model on the market. Thus, when a new shaver hand piece is developed by a given manufacturer, a new shaver detection device must also be developed by DePuy Mitek in order to properly operate the fluid management system for its intended purpose.
Accordingly, there exists a need in the art for an improved fluid management system which does not require a separate custom-made detection device for each surgical device on the market.
Also in conventional fluid management systems, switching between the operational and non-operational outflow fluid pathways (i.e., the cannula and device tubes) is physically accomplished by a pinch mechanism, commonly including a rotating wheel located between the two tubes. The wheel is configured to switch between restricting—or “pinching off”—one of the two tubes, while allowing fluid to travel through the other. This configuration results in a complicated procedure for connecting the tubes to the fluid management system. For example, conventional pumps require that the user install one outflow tube first, press a pinch button to move the pinch mechanism, and then load the second outflow tube.
Accordingly, there exists a need in the art for an improved fluid management system and method for easing installation and replacement of outflow tubes.
The pressure at which fluids are introduced at an operative site is preferably stable over a period of time, and capable of being specified depending upon the use. Prior art systems include pressure sensors to detect an inflow pressure at the operative site, but this requires additional intrusive components at the operative site. The pressure can instead be estimated based upon the pressure at the output of an inflow pathway of an inflow/outflow pump. However, these inflow pressure estimates can be inaccurate, especially when a surgical device is operational at the operative site.
Accordingly, there exists a need in the art for improved devices and methods for compensating for variations in pressure levels at the operative site.